Why Does My House Smell Musty?

Few things are more irritating than problems you can't make go away. Smells in your home are an example. Even though you can eventually go nose blind to persistent odors, it can deter you from wanting to host people in your home. If your house has a musty smell, you aren't alone.

South Central Services has insulated hundreds of homes with spray foam insulation. We regularly collaborate with customers to solve these kinds of issues in their homes. Whether you're struggling with cold floors, high energy bills, poor air quality, or musty smells, there are solutions to the root cause of your frustration.

By the end of this article, you will know:

• What a musty smell indicates
• How to test for mold or mildew
• Where to look for moisture infiltration
• Who to contact to fix the root issue

What Does A Musty Smell In A Home Mean?

A musty smell is almost always an indicator of unmanaged moisture. This moisture could either be liquid water or vapor.

Unmanaged moisture often presents as mold or mildew. If unmanaged moisture reaches the point of smelling musty, it has likely reached the stage of mold or mildew.

The source of the unmanaged moisture could be the roof, walls, attic, basement, or crawl space.

How To Address A Musty Smell In Your Home

There are two key steps to addressing the musty smell in your home: testing your air and finding the source. Let's examine them in more detail.

Step 1: Test Your Air

It is important to start the process of addressing the musty smell by testing your air. While the musty smell often indicates mold or mildew, you need to complete a test to be certain.

Some mold remediation companies may offer air testing. Check the websites of mold remediation companies in your area for a list of services.

If there are no professional air tests available, you may be able to purchase a DIY air test kit instead. Lowe’s and Home Depot both sell DIY mold test kits for approximately $10. There are also professional-grade kits for sale from other companies. Professional-grade kits tend to be more expensive than home improvement store versions.

No matter which route you take to test your air, the goal is to determine if mold is present in your air. The presence of mold means remediation will be necessary.

Step 2: Identify The Source Of Moisture

Once you've tested your air, it is time to identify the source of moisture.

If the musty smell in your home results from mold, finding the source can narrow down the work for the mold remediation company.

If the musty smell has not progressed to mold yet, finding the source will allow you to prevent mold growth in your home.

Common Sources Of Moisture Infiltration

Where are you supposed to look for moisture infiltration? There are six common culprits for moisture, whether liquid water or water vapor.

1. Window flashing
2. Roofs
3. Basements
4. Crawl spaces
5. Siding
6. HVAC systems

Let's examine each source in more detail and learn who to call if moisture penetrates there. Remember, if mold is present in your home, contact a specialist.

1. Window Flashing

Window flashing is the term for the waterproofing materials placed around windows. Cracks and crevices around windows can lead to moisture infiltration. If you have flashing issues around a window, liquid water can get around your window and leech into your wall cavity.

If there is an odor or peeling paint around your window, it is most likely a flashing issue.

For flashing issues, you'll want to contact a contractor specializing in a home's exterior. An example would be a siding contractor.

2. Roof Leaks

Roof leaks are often easy to identify. If you need buckets to collect water when it's raining, you have a roof leak. A leaky roof can be frustrating for homeowners. Not only do you have to be mindful of your home when the weather changes, but the leaking water can also cause damage to the rest of your home.

You'll want to contact a roofing contractor if you have a leaky roof, no matter how small the leak.

3. Basement Leaks

There are two types of basement leaks: groundwater infiltration and vapor infiltration. The type of leak you are experiencing in your basement will determine the approach to fixing it.

If you have groundwater infiltration, liquid water seeps into your basement with heavy rains. This is most likely because the water is being directed towards your foundation. Correct the negative grade of the ground that pushes water toward your home. Also, check your downspouts for clogs. A clogged downspout will dump water in front of your house.

If you have vapor infiltration, you may notice sweat on your walls. Vapor transfer in your basement will require a different solution than groundwater.

Some basement leaks can be solved DIY. However, you can also contact an insulation contractor or waterproofing company.

4. Crawl Space

Crawl spaces are notorious for their unpleasant odor. Additionally, crawl spaces often struggle with pest infestations, mold, and mildew. If your home has a crawl space that has not been encapsulated, there is a high probability that the musty odor originated there.

The reason why crawl spaces are so musty smelling is because they are exposed to all of the elements. The average crawl space is not a conditioned space with heating and cooling running through it or any effective insulation. Instead, moisture and temperature differences in the air impact the climate of the crawl space itself.

All of that unpleasant and unclean air is sucked into your living space as a replacement for air that escapes through other air leakage.

We recommend the encapsulation method to solve crawl space problems. By making the crawl space a part of the home's conditioned space, any air that cycles from that area of the house is clean and temperature controlled.

Reach out to an insulation contractor about crawl space encapsulation. Be certain to address any mold concerns with your contractor, if mold is present in your crawl space.

5. House Siding

It is a common misconception that siding is waterproof. Many homeowners and contractors believe that siding can prevent water transfer once interlocked and placed against a building. Unfortunately, house siding is not waterproof. The siding should have a weatherproof barrier underneath it.

Siding itself may be waterproof. However, once installed, it is nearly impossible to make the complete siding assembly waterproof. There are too many seams and transitions in the siding.

Contractors who work with siding professionally usually understand the installation needs for siding to prevent water from getting around the siding.

When water infiltrates your siding, moisture can sit and soak into the walls of your home. Depending on how your home is constructed, that moisture may cause mold growth on wood, insulation, or the siding itself.

If you eliminate other areas of the home as the culprit of the musty odor and suspect your siding, contact a contractor who works specifically with the home's exterior.

6. Oversized HVAC System

An oversized HVAC system can struggle to manage humidity in the home. Excess humidity can cause mildew and mold, just like a water or vapor leak.

Even if an HVAC system is appropriately sized for the home, it is also possible that the coil of the HVAC system may need to be cleaned.

If the root cause of your musty smells is your HVAC system, you’ll notice excessive humidity in your house during the summer months. There will also be an increase in smell when your HVAC unit is running.

Reach out to an HVAC contractor to evaluate your system's capacity and clean the coil.

The Bottom Line About Fixing Musty Odors In Your Home

No one wants their home to smell. Even though we go nose blind to smells rather quickly, an unpleasant odor can indicate air quality problems. It also makes inviting others into our homes uncomfortable.

Musty odors result from water infiltration, whether in a liquid or vapor form. Common areas where moisture infiltrates include window flashing, roofs, basements, crawl spaces, and siding.

If you want to address the musty smell in your home, you need to test your air for mold and find the source of water infiltration. From there, you can contact appropriate professionals to help solve the issue in your home.

Think the problem might be your crawl space? Your next step is to:

• Learn what crawl space encapsulation is
• Decide between encapsulation or insulating the crawl space ceiling
• Find out if you could encapsulate your crawl space DIY